References
- Groff , J. H. , Schlecht , P. C. and Shulman , S. 1990 . Laboratory Reports and Rating Criteria for the Proficiency Analytical Testing (PAT) Program , Cincinnati, OH : National Institute for Occupational Safety and Health . DHHS (NIOSH) Pub. No. 91–102
- Groff , J. H. and Schlecht , P. C. 1992 . PAT Program Report: Background and Current Status . Appl. Occup. Environ. Hyg. , 7 ( 3 ) : 156 – 158 .
- National Institute for Occupational Safety and Health . 1984 . “ Silica, Crystalline, Respirable: Method 7500 ” . In NIOSH Manual of Analytical Methods. , 3rd rev. ed. , Edited by: Eller , P. M. Cincinnati, OH : National Institute for Occupational Safety and Health . DHHS (NIOSH) Pub. No. 84–100